The present invention relates to methods for displaying 3D (three-dimensional) data in a two-dimensional space. More specifically, but without limitation thereto, the present invention relates to a method for displaying 3-D data on a video display terminal and overlaying the 3-D data with an interactively adjustable visual boundary surface.
In evaluating the performance of an antenna design, it is desirable to examine the far field pattern radiated by the antenna. The far field radiation pattern may be computed using electromagnetic equations and by measuring the antenna pattern at an antenna pattern range. The far field radiation pattern of an antenna defines the performance of the antenna for a given environment. If the antenna is situated in free space, then it has an associated ideal radiation pattern. In practical applications, however, the antenna is surrounded by interfering structures. For example, high frequency (HF) antennas on a ship are interfered with by the structure of the ship. A measurement of the antenna pattern is typically made by modeling the antenna and the ship on which the antenna is mounted to determine how the structure of the ship affects the antenna pattern. Energy from the radiating antenna couples into the structure of the ship and is re-radiated, creating blockages or nulls in the antenna pattern that may result in extreme degradation of the far field antenna pattern.
An antenna pattern test range typically includes a small scale model of the antenna, the interfering structures, and an electromagnetic sensor. The sensor is typically moved along a track to measure the relative magnitude and phase of electromagnetic radiation transmitted by the antenna at a wavelength appropriate to the scale of the model. The signal received by the sensor is measured over a wide range of elevation and azimuth angles as the sensor is moved along the track. The sensor relays the measurements to a data logger that records the data in a file for analysis and display.
The performance of a communications system is closely linked to the performance of its antennas. A need therefore exists for a method to evaluate antenna performance and to identify any blockages or sidelobes in the antenna pattern.